You can gain strength and more.

If you’re over 40, the first time you heard the word “isometrics” was probably in the context of an exercise program your Dad used to get the 1970s version of jacked. Contract and hold a muscle, the thinking went, and you’d get bigger, stronger, and leaner — no movement necessary. Isometrics was such a hot trend a few decades ago that it even warranted an appearance in the 1966 Paul Newman flick Harper.

That type of thinking has gone the way of bellbottoms because, it turns out, muscles need movement to grow noticeably bigger and stronger. Strike one against isometrics. Strike two: Isometric contractions burn fewer calories than muscles at rest.

That’s partly why the isometrics trend went away as a viable program-builder — but that doesn’t mean you should discard this simple, anywhere-anytime form of exercise. There’s still a place for isometrics in your workout program, even throughout your day. Here are five:

1

Recovery From Injury

Suffer a shoulder or knee injury, and you’ll quickly learn that the first stage of rehab is all about isometrics. Mess up your knee, and the doc will have you squeeze your quads for a few seconds, then release the contraction. You’ll do that again. And again. And again. Your doctors don’t count reps either; they count time. Usually in hours.

So if you took a bad step playing touch football, an isometric muscle contraction is a fairly safe first step in your recovery. If it’s your knee that’s wonky, try squeezing your quads hard for 10 to 30 seconds at various joint angles: leg straight, leg bent 90 degrees, leg fully bent. The boon of this approach is that it’s safe: your joints aren’t moving and you aren’t bearing any weight. Squeeze away.

2

Fixing Your Posture

All muscles are movement-producers, but some work best as movement-preventers. This is especially true of core muscles, whose primary function is to protect your spine by preventing your trunk from twisting and bending excessively.

The postural muscles of your mid-back and lower back—which spend most of your waking hours in partial isometric contraction—also benefit from this brand of training. After a long day slumped over a computer, stand up, raise your arms to eye level, extend your hips and lower back, pinch your shoulder blades together, and hold for 30 seconds. You’ll feel like a new man.

3

Improve Your Mind-Muscle Connection

Functional training gurus disparage bodybuilding phrases like “mind-muscle link, “ but you should embrace anything that works. Anyone who’s lifted a weight has long known that certain muscles are easier to feel than others. For some guys, biceps and pecs are easier to sense; for others, it’s calves and hamstrings.

Isometrics are an effective (and convenient) way to improve that feeling of control and connection in your weaker muscle groups — any time, any place. Waiting in line at the grocery store? Squeeze your shoulder blades down and back to feel your lower traps working. Stuck in traffic? Push against the steering wheel and contract your pecs.

The oft-neglected glutes — which tend to get flaccid when you sit on them all day — are among the muscle groups that benefit the most from this type of work. You can even squeeze them while you’re sitting down—either by driving your knees outward against the legs of your desk, or by tucking your pelvis and squeezing your cheeks together. Sometimes it’s good to be a tight-ass.

4

Get Stronger

Yes, muscles need movement to get noticeably stronger — but research does show that isometric contractions strengthen a muscle around the range of motion in which you’re contracting that muscle. If you isometrically contract your quads in a legs-straight position, they’ll get stronger in that locked-out position.

You can’t use this to pack on a ton of muscle, but you can use this to your advantage to gain strength. Many major bodybuilding lifts have a sticking point, where your muscles are weakest. Think of where the bar gets stuck when you’re benching your heaviest weights.

You can train this area: If your bench press progress gets stalled, try a set or two of isometric contracts in the mid-range of the exercise (which is typically when most guys fail). Here’s how to do it: set the bench in the power rack with the crossbars just above mid-press height and the empty bar in the safety catches below the crossbars.

Then lie back, unrack the bar, and push it as hard as possible against the crossbars for 10 to 30 seconds. Over time, the sticking point won’t stick any more—and your bench-press numbers will soar. This approach can also work for squats and deadlifts.

Another route to heavier weights: Hold a challenging weight in the locked-out position, another type of isometric contraction. This builds connective tissue strength and gets you accustomed to holding bigger weights than you’re used to.

Try it like this on the bench press: Grab a loaded bar that’s 5 to 10 percent more than your proven one-rep max. Lock it out (make sure to use a spotter or a power rack) and hold it there for 10 to 30 seconds. Your joints and tendons will gradually respond to the new loading, and in a few weeks you’ll be ready to push the bigger weights for real.